JPH02140111A - Rice cooker - Google Patents

Abstract

PURPOSE:To execute ideal rice cooking without the nonuniformity of the rice cooking by improving the watt density of an electric heater for a part to correspond to the central part and outer circumferential part of a bottom surface in a pot. CONSTITUTION:An electric heater 7 is equipped with a top plate 8, which is composed of the metal plate of SUS304, and a hole part 8a is provided in the central part of the top plate 8. Then, ribs 8b and 8c are provided on an inner circumferential surface and an outer circumferential surface. An spiral groove 9a is provided in a heat insulating substrate 9, which is composed of a heat insulator to use silica-alumina fiber as a main component, and a hole part 9b is provided in a central part. For the groove 9a, an outer circumferential part and an inner circumferential part are formed tight and the watt density is arranged to be high in the part to correspond to the outer circumferential part and central part of the bottom surface in a pot 5. A heating wire 10 is arranged in the groove 9a of the heat insulating substrate 9. Since the watt density is made high in the part to correspond to the outer circumferential part and central part of the bottom surface in the pot 5, the circulation of water and rice in the internal part of the pot 5 is generated not only in the outer circumferential part but also in the central part. Thus, the nonuniformity of the rice cooking can be almost prevented and the rice cooking without the nonuniformity can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a rice cooker 21\- used in general households.
In particular, the present invention relates to a rice cooker with improved cooking performance using an electric heater.

Conventional technology Traditionally, two main types of electric heaters have been used for rice cookers: (1) a cast aluminum heater in which a sheathed heater is embedded in cast aluminum (2) a sheathed heater (high temperature type); (1) When using a cast aluminum heater, a direct heating method is used where the pot and electric heater come into direct contact, and when using a sheathed heater (2), an indirect heating method is used where the pot and electric heater do not come into contact. The reality is that the position of the pot and electric heater is changed depending on the type of electric heater used.

Problems that the investigation aims to solve However, in the direct heating method (1) using a cast aluminum heater, the pot and electric heater are in contact with each other, so although the heat efficiency is excellent, the heat from the electric heater to the pot is Because heat transfer occurs through heat conduction, heat transfer may be unbalanced depending on the degree of contact between the pot and the electric heater, or depending on the location, such as the part of the temperature sensor installed in the center of the electric heater or the top of the pot. Since the rice tends to be cooked unevenly, there is a problem that the overall taste deteriorates.

In addition, strict dimensional accuracy is required to ensure that the electric heater and pot are in close contact with each other, which increases costs.Furthermore, if the heat transfer becomes unbalanced due to deformation or corrosion during use, the uneven cooking becomes even worse. There was a problem.

On the other hand, in the indirect heating method (2) that uses a high-temperature type sheathed heater, heat transfer from the electric heater to the pot occurs through thermal radiation, so areas close to the electric heater become sticky, and the electric heater There was a problem in that the farthest parts (the upper part of the pot) were unevenly cooked, such as hardness, and the taste was poor.

Furthermore, in order to improve this, if the sheathed heater is made into a spiral shape, modifications and fixing fittings will be required to obtain flatness of the heater, which will increase the cost.

Furthermore, since the heating area of the heater is small, the temperature of the heater itself becomes high, and as a result, the heat shielding structure of the main body becomes large-scale.

For these reasons, the present inventors have already developed a heat insulating base 11 made of a heat insulating material containing silica-alumina fiber as the main component and alumina sol as the main binder, as shown in FIGS. 4 and 5. We are proposing a rice cooker that uses an electric heater.

However, in this case, the spirally wound heating wire 12
is spirally wound around the groove 11a of the heat insulating base 11, and the watt density of the electric heater gradually decreases from the outer periphery to the center of the pot. In a rice cooker, convection in the pot only occurs from the outer periphery toward the center, and as shown in Figure 6, the rice is well-cooked at the outer periphery and upper layer a, but at the center and from the middle to lower layer. The entire portion was hard and the rice could not be cooked evenly.

The present invention has been made to solve the above-mentioned problems and aims to provide a rice cooker that can ideally cook rice without uneven cooking.

Means for Solving the Problems In order to solve the above problems, the present invention provides a top plate made of a metal plate, a spirally wound heating wire, and a silica-alumina material having a groove in which the heating wire is spirally arranged. The main component is fiber,
An electric heater consisting of a heat insulating base made of a heat insulating material whose main binding material is alumina sol, a storage case made of a metal plate that houses the heat insulating base, a pot that houses the food to be cooked, and a protective frame that houses the pot. A heating space is formed between the protective frame and the pot, and the electric heater is provided within the heating space at a predetermined distance from the steel, and the watt density of the electric heater is is constructed such that the portions corresponding to the center and outer peripheral portions of the bottom surface of the steel are higher.

Effects By having the above-described configuration, the present invention can freely change the heat generation pattern of the electric heater used by changing the groove shape of the heat insulating base. Since the wattage density at the outer periphery is increased, convection of the water and rice inside the pot occurs not only at the outer periphery but also at the center, resulting in evenly cooked rice after the rice is cooked. It will be possible.

EXAMPLES Hereinafter, specific examples of the present invention will be explained based on FIGS. 1 to 3. In the figure, a substantially bottomed cylindrical protective frame 3 serving as a pot storing section is disposed inside a main body 1 having an open top surface and a substantially bottomed cylindrical shape with a heat insulating material 2 interposed therebetween. The outer periphery of the upper end of the protective frame 3 is fitted into the annular upper frame 4 made of heat-resistant plastic, which is fitted around the inner periphery of the upper end.

Further, the pot 5 having an outwardly projecting flange 6 formed on the upper opening edge is housed within the protective frame 3 by placing the flange 6 on the upper surface of the upper frame 4. Further, the outer circumferential surface of the steel 6 is black-treated with black alumite using an inorganic heat-resistant dye.

The electric heater 7 also includes a top plate 8 made of a 5US304 metal plate, and a hole 8a is provided in the center of the top plate 8, and a lip sb is provided on the inner and outer circumferential surfaces.
, sc are provided, respectively, and a female thread 8d is provided inside the outer peripheral surface. A heat insulating base 9 made of a heat insulating material mainly composed of silica-alumina fibers is provided with a spiral groove 9a and a hole 9b in the center. As shown in FIG. 3, the groove 9a is formed so that the outer circumference and inner circumference are dense, and the wattage density is high in the portion corresponding to the outer circumference and the center of the bottom of the pot 5. care has been taken to ensure that Further, a spirally wound heating wire 10 is disposed in a groove 9a provided in the heat insulating base 9. A heat insulating base 9 on which the heating wire 10 is arranged
Storage case 1 made of 5US430 metal plate for storing
A hole 11a is provided in the center of 1, and
Ribs 11b and 11C are provided on the inner peripheral surface and the outer peripheral surface, respectively. Said top plate 8. The heat insulation base 9 and the storage case 10 have central holes 8a and 9b provided in each.
, 11b are integrated by a fixing ring 19 to form the electric heater 7. Moreover, the electric heater 7 with the above content is
It is located in the heating space 12 formed between the protective frame 3 and the pot 6, and is supported by a support member (not shown) at the bottom of the protective frame 3 at a predetermined distance from the pot 5. .

The protective frame 3 includes a heat-sensitive element 13 for detecting the end temperature of rice cooking.
is attached, and this heat-sensitive element 13 is interlocked with a lever 14, which turns on and off a microswitch 15 that controls energization of the electric heater 7. Further, a lid 18 is attached to the main body 1 at an opening on the display plate surface so as to be openable and closable.

Next, the operation of the rice cooker of the present invention having such a configuration will be explained. First, store washed rice and water in the pot 5, then store the pot 5 in the protective frame 3, and place the lid 1.
Close 8. When the operation button 17 is pressed, the lever 14 rotates, and the heat-sensitive element 13 linked to this lever 14 operates, and the rice cooking mode is activated.
The switch 5 is turned on, and the electric heater 7 is energized.

When the electric heater 7 generates heat, the air in the sealed heating space 12 is heated, and the pot 5 is heated via this heated air. By heating this pot 5, rice is cooked. When all the water in the pot 5 is absorbed by the rice, the bottom of the pot 6 becomes empty and the temperature rises rapidly.

At this time, the temperature of the heat-sensitive element 13 also rises, and the lever 14 is pushed down, so the microswitch 15 is opened and the electricity to the electric heater 7 is stopped, completing the rice cooking.

During such rice cooking, in the embodiment of the present invention, the shape of the groove 9a of the heat insulating substrate 9 is taken into consideration, and the watt density is set to be high in the portions corresponding to the outer periphery and the center of the bottom of the pot 6. Therefore, convection of water and rice inside the pot 5 occurs not only at the outer periphery but also at the center, and as a result, the uneven cooking that has been seen in the past almost never occurs, and the ideal result is that there is no uneven cooking. This makes it possible to cook rice in a variety of ways.

108-7 Note that the groove 9 of the heat insulating base 9 shown in the embodiment of the present invention
The pattern a is not particularly limited to this, and any pattern may be used as long as it is designed to have a high wattage density in the center and the outer periphery of the pot 5.

Effects of the Invention As is clear from the description of the above embodiments, the present invention has a top plate made of a metal plate, a spirally wound heating wire, and a groove for distributing the heating wire in a spiral shape. and an electric heater consisting of a heat insulating base made of a heat insulating material containing silica-alumina fiber as a main component and alumina sol as a main binder, and a storage case made of a metal plate that houses this heat insulating base, and storing food to be cooked. It comprises a pot and a protective frame for storing the pot, a heating space is formed between the protection frame and the pot, and the electric heater is placed in the heating space at a predetermined distance from the pot. In addition, the watt density of this electric heater is configured such that the portion corresponding to the center and outer periphery of the bottom of the pot is higher, thereby providing a rice cooker that can ideally cook rice without uneven cooking. It is something that can be done.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of a rice cooker showing an embodiment of the present invention;
Figure 2 is a sectional view of the electric heater in the rice cooker, Figure 3 is a top view showing the groove pattern of the heat insulating base of the electric heater,
Fig. 4 is a cross-sectional view of the electric heater in a conventional rice cooker, Fig. 6 is a top view showing the groove pattern of the heat insulating base of the electric heater, and Fig. 6 shows the nine states of cooked rice during conventional rice cooking. FIG. 3...Protective frame, 5...Pot, 7...
...Electric heater, 8...Top plate, 9...
Heat insulation base, 9a...groove, 1°...heating wire, 11...storage case, 12...heating space section.

Claims (1)

[Claims] A heat insulating material that has a top plate made of a metal plate, a spirally wound heating wire, and a groove in which the heating wire is arranged in a spiral shape, and that has silica-alumina fiber as its main component and alumina sol as its main binding material. The electric heater includes a heat insulating base consisting of a heat insulating base, a storage case made of a metal plate for housing the heat insulating base, a pot for storing food to be cooked, and a protective frame for housing the pot, the protective frame and A heating space is formed between the pot and the electric heater is provided within the heating space at a predetermined distance from the pot, and the watt density of the electric heater is set to the center of the bottom of the pot. A rice cooker configured so that the part corresponding to the outer periphery is higher.